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Tricalcium aluminate (C3A) and tricalcium silicate (C3S) with gypsums play an important role in the hydration of oil well cement. This study aims to assess the influence of C3S and C3A with various gypsums on the hydration of oil well cement at 30, 50, and 80 °C through the analyses of hydration heat evolution by isothermal calorimetry analysis, setting and thickening times, strength, and hydration products by X-ray diffraction. The result reveals that C3A hydrates, in the presence of gypsums, rapidly at 80 °C to produce the C3AH6 phase leading to higher heat evolution. The conversion of AFt to AFm is observed in oil well cement paste at 50 °C. An increase in C3A leads to an increase in compressive strength and a decrease in permeability at 80 °C. An increase of C3S leads to the reduction of cumulative heat evolution and early compressive strength before 28 d. Gypsums shorten cement setting and thickening times opposite to the commonly known retardation effect due to the lower content of C3A and its acceleration on C3S hydration. Dihydrate and hemihydrate gypsums show a greater promotion effect on strength at 30 and 50 °C, while anhydrous gypsum presents a greater enhancing effect at 80 °C. Gypsum increases the permeability while the others show an unobvious effect at 80 °C. [ABSTRACT FROM AUTHOR]

An important aspect of the pathophysiology of early brain damage (EBI) after subarachnoid hemorrhage (SAH) is inflammasome-mediated neuroinflammation. It has been demonstrated that C3aR activation exacerbates neuronal damage in a number of neurological disorders. This study aims to explore the role of C3a in activating the NLRP3 inflammasome and exacerbating neuroinflammation after SAH. Preprocessing of RNA-seq transcriptome datasets using bioinformatics analysis, and screening of differentially expressed genes between SAH patients and healthy individuals from the GEO database. Internal carotid artery puncture was performed to establish SAH models in rats and mice. SAH grading, neurological scoring, brain water content, behavioral analysis, and assessments using ELISA, Western blot, immunofluorescence, and immunohistochemistry were conducted. An invitro model of SAH was induced in BV-2 cells treated with heme (200 μM). The mechanism of C3a in post-SAH neuroinflammation was studied by interfering with and inhibiting C3aR. Results showed that the expression of C3aR was upregulated in the GEO dataset (serum of SAH patients) and identified as a key differential gene in SAH. Further, elevated levels of C3a were found in the cerebrospinal fluid of clinically collected SAH patients. In the cerebral cortex and/or serum of SAH rats, expression of C3a, IL-1β, IL-6, TNF-α, CD11b, and Ki67 were significantly increased, while IL-10 was significantly decreased. Correlation analysis revealed that C3a showed negative correlation with IL-10 and positive correlation with IL-1β, IL-6, TNF-α, CD11b, and Ki67. After stimulation with heme, protein levels of C3a increased in BV-2 cells. Interfering with C3aR significantly reduced LDH release, IL-1β secretion, Caspase1 activation, levels of NLRP3 expression and ASC oligomerization, and ATP release after heme stimulation in BV-2. Subsequently, the addition of inhibitors of ERK1/2 phosphorylation demonstrated that C3a promotes ATP efflux by activating ERK1/2 phosphorylation, thereby activating P2X7. Further addition of JNJ-55308942 (a P2X7R antagonist) revealed that C3a activated the NLRP3 inflammasome via P2X7. Finally, administering SB290157 (a C3aR inhibitor) invivo effectively alleviated brain edema, reduced mortality, improved Garcia score, ameliorated motor dysfunction, and suppressed inflammation and NLRP3 inflammasome activation in mice after SAH. Overall, C3a exacerbates EBI-associated NLRP3 inflammasome and neuroinflammation via the C3aR-ERK-P2X7 pathway after SAH. Inhibiting C3aR may serve as a one possible treatment approach to alleviate SAH after EBI. [ABSTRACT FROM AUTHOR]

Calcium aluminate phases have a particular effect on the early heat release during setting initiation and have a substantial influence on the further workability of ordinary Portland cement. The nature of the calcium aluminate hydration products and its kinetics strongly depends on sulfate content and humidity. The effect of mineralisers on melt formation and viscosity is well described for calcium silicate systems, but information is still lacking for calcium aluminates. Therefore, the synergistic effect on the crystal structure and hydration mechanism of the tricalcium aluminate phase of the addition of mineralizers, i.e. Li2O, CuO, SO3 to the raw meal is here investigated. Co-doped calcium aluminate structures were formed during high-temperature treatment. Thermal analysis (TG–DTA and heating microscopy) was used to describe the ongoing high-temperature reaction. Resulting phase composition was dependent on the concentration of the mineralizer. While phase pure system was prepared with low mineralizer concentrations, with increasing mineralizer content the secondary phases were formed. Raman spectroscopy and XPS analysis were used to investigate the cation substitution and to help describe the cations bonding in co-doped calcium aluminate system. Prepared powders have been hydrated in a controlled manner at different temperatures (288, 298, 308 K). The resulting calorimetric data have been used to investigate the hydration kinetics and determine the rate constant of hydration reaction. First-order reaction (FOR) model was here applied for the activation energy and frequency factor calculations. The metastable and stable calcium aluminate hydrates were formed according to initial phase composition. In phase pure systems with low S content, the formation of stable and metastable hydrates was depended on the reaction temperature. Conversely, in systems with secondary phases and higher S content, the hydration mechanism resembled that which appears in calcium sulfoaluminates. [ABSTRACT FROM AUTHOR]

The TLQP-21 neuropeptide has been implicated in functions as diverse as lipolysis, neurodegeneration and metabolism, thus suggesting an important role in several human diseases. Three binding targets have been proposed for TLQP-21: C3aR1, gC1qR and HSPA8. The aim of this review is to critically evaluate the molecular identity of the TLQP-21 receptor and the proposed multi-receptor mechanism of action. Several studies confirm a critical role for C3aR1 in TLQP-21 biological activity and a largely conserved mode of binding, receptor activation and signaling with C3a, its first-identified endogenous ligand. Conversely, data supporting a role of gC1qR and HSPA8 in TLQP-21 activity remain limited, with no signal transduction pathways being described. Overall, C3aR1 is the only receptor for which a necessary and sufficient role in TLQP-21 activity has been confirmed thus far. This conclusion calls into question the validity of a multi-receptor mechanism of action for TLQP-21 and should inform future studies. [ABSTRACT FROM AUTHOR]

Ischemic stroke is a major cause of disability. No efficient therapy is currently available, except for the removal of the occluding blood clot during the first hours after symptom onset. Loss of function after stroke is due to cell death in the infarcted tissue, cell dysfunction in the peri-infarct region, as well as dysfunction and neurodegeneration in remote brain areas. Plasticity responses in spared brain regions are a major contributor to functional recovery, while secondary neurodegeneration in remote regions is associated with depression and impedes the long-term outcome after stroke. Hypoxic-ischemic encephalopathy due to birth asphyxia is the leading cause of neurological disability resulting from birth complications. Despite major progress in neonatal care, approximately 50% of survivors develop complications such as mental retardation, cerebral palsy or epilepsy. The C3a receptor (C3aR) is expressed by many cell types including neurons and glia. While there is a body of evidence for its deleterious effects in the acute phase after ischemic injury to the adult brain, C3aR signaling contributes to better outcome in the post-acute and chronic phase after ischemic stroke in adults and in the ischemic immature brain. Here we discuss recent insights into the novel roles of C3aR signaling in the ischemic brain with focus on the therapeutic opportunities of modulating C3aR activity to improve the outcome after ischemic stroke and birth asphyxia. [ABSTRACT FROM AUTHOR]

In this observational case-control study, circulating levels of complement factors C3a and C5a and leukotriene B4 (LTB4) were analysed in abdominal aortic aneurysm (AAA) patients regarding their association with diagnosis and prognosis. Serum C5a was significantly raised in AAA patients compared to healthy controls—median 84.5 ng/ml (IQR = 37.5 ng/ml) vs. 67.7 ng/ml (IQR = 26.2 ng/ml), p = 0.007—but was not elevated in patients with athero-occlusive disease. Serum C5a levels correlated significantly with the increase in maximum AAA diameter over the following 6 months (r = 0.319, p = 0.021). The median growth in the lowest quartile of C5a (< 70 ng/ml) was 50% less compared to the highest C5a quartile (> 101 ng/ml): 1.0 mm/6 months (IQR = 0.8 mm) vs. 2.0 mm/6 months (IQR = 1.5 mm), p = 0.014. A log-linear mixed model predicted AAA expansion based on current diameter and C5a level. To our knowledge, this is the first study linking complement activation, in particular C5a serum level, with AAA progression. [ABSTRACT FROM AUTHOR]

Lyme borreliosis (LB) is caused by Borrelia burgdorferi and infection may lead to not only a large variety of clinical manifestations but also a subclinical outcome. The aim of the present study was to investigate if there is a constitutional difference in complement activation between individuals with previous subclinical Lyme borreliosis (SB) and patients previously diagnosed with Lyme neuroborreliosis (LNB). Lepirudin plasma for activation studies was collected from 60 SB individuals and from 22 patients pre-diagnosed with LNB. The plasma was incubated with live Borrelia spirochetes of two strains (complement sensitive B. garinii Lu59 and complement resistant B. afzelii ACA1). Complement factor C3 was measured in non-activated lepirudin plasma with immune-nephelometry and C3a and sC5b-9 generated during complement activation were measured by enzyme-linked immunosorbent assay. We found that the complement sensitive Lu59 induced higher complement activation than the complement resistant ACA1 when measuring activation products C3a and sC5b-9 in SB and LNB patients, p < 0.0001. No significant difference was found between SB and LNB patients in systemic levels of C3. Furthermore, SB individuals generated a higher activation of C3 cleavage to C3a (C3a/C3 ratio) than LNB patients after activation with ACA1, p < 0.001, but no significant differences were found in response to Lu59. In conclusion, Lu59 induced higher complement activation than ACA1 and individuals with previous SB showed increased generation of C3a compared with patients with previous LNB. In our study population, this mechanism could lead to less elimination of spirochetes in LNB patients and thereby be a factor contributing to the clinical outcome. [ABSTRACT FROM AUTHOR]

The complement system plays an important role in cardiovascular disease in patients on hemodialysis. Vascular calcification is also one of the major causes of cardiovascular disease. We want to investigate the relationship between complement activation and vascular calcification in dialyzed patients. One hundred eight hemodialysis patients and 65 heathy controls were enrolled prospectively. Plasma C3a, C5a, mannose-binding lectin (MBL), and membrane attack complex (MAC or C5b-9) levels were detected using ELISA. Plasma C3c, fB, fH, C1q, and C4 levels were measured by immunity transmission turbidity. Abdominal aortic calcification (AAC) was measured by abdomen lateral plain radiograph, and the AAC score was calculated. We identified increased level of MBL and decreased level of C3c and complement factor B compared with normal control. However, C1q, complement factor H, and C4 levels remained at a similar level compared with individuals with normal renal function. The C3a and C5a levels increased, without change of MAC. Forty two of 108 HD patients had the AAC score. C3a levels were correlated with AAC score (r = 0.461, p = 0.002). The median C3a concentration was 238.72 (196.96, 323.41) ng/mL. When evaluated as AAC categories (≤ 4, > 5) with ordinal logistic regression, univariate analyses revealed that higher C3a levels were associated with severe AAC, while multivariate analyses adjusted for age, sex, and calcium level showed that higher C3a levels (OR, 6.28 (1.25–31.69); p = 0.03) were associated with severe AAC. The areas under the curve (AUC) for C3a to diagnose severe abdominal aortic calcification were 0.75(0.58–0.92, 0.01). The complement system was activated in patients on hemodialysis. Higher C3a levels are independently associated with severe AAC. Plasma C3a might have a diagnostic value for the severe AAC in HD patients. [ABSTRACT FROM AUTHOR]

The in vitro generation of terminally differentiated hepatocytes is an unmet need. We investigated the contribution of oxygen concentration to differentiation in human liver cell lines HepaRG and C3A. HepaRG cells were cultured under hypoxia (5%O2), normoxia (21%O2) or hyperoxia (40%O2). Cultures were analysed for hepatic functions, gene transcript levels, and protein expression of albumin, hepatic transcription factor CEBPα, hepatic progenitor marker SOX9, and hypoxia inducible factor (HIF)1α. C3A cells were analysed after exposure to normoxia or hyperoxia. In hyperoxic HepaRG cultures, urea cycle activity, bile acid synthesis, CytochromeP450 3A4 (CYP3A4) activity and ammonia elimination were 165-266% increased. These effects were reproduced in C3A cells. Whole transcriptome analysis of HepaRG cells revealed that 240 (of 23.223) probes were differentially expressed under hyperoxia, with an overrepresentation of genes involved in hepatic differentiation, metabolism and extracellular signalling. Under hypoxia, CYP3A4 activity and ammonia elimination were inhibited almost completely and 5/5 tested hepatic genes and 2/3 tested hepatic transcription factor genes were downregulated. Protein expression of SOX9 and HIF1α was strongly positive in hypoxic cultures, variable in normoxic cultures and predominantly negative in hyperoxic cultures. Conversely, albumin and CEBPα expression were highest in hyperoxic cultures. HepaRG cells that were serially passaged under hypoxia maintained their capacity to differentiate under normoxia, in contrast to cells passaged under normoxia. Hyperoxia increases hepatocyte differentiation in HepaRG and C3A cells. In contrast, hypoxia maintains stem cell characteristics and inhibits hepatic differentiation of HepaRG cells, possibly through the activity of HIF1α. [ABSTRACT FROM AUTHOR]

Background: The chronic inflammation plays an important role in heart failure and complement components might be useful markers of the prognosis. We set out to evaluate their predictive value in the clinical outcomes of patients with cardiac resynchronization therapy (CRT). Methods: We determined the complement levels C3, C3a, sC5b-9 and also the N-terminus of the prohormone brain natriuretic peptide (NT-proBNP) of 126 heart failure patients in a prospective, single-center observational study before and 6 months after CRT implantation. Results: CRT reduced the C3a [212.5 (148.2-283.6) vs. 153 (119.8-218.3) ng/mL, p < 0.0001] and the sC5b-9 levels [296.9 (234.2-358.8) vs. 255.1 (210.1-319.0) ng/mL, p = 0.0006], but not the total C3 levels [1.43 (1.26-1.61) vs. 1.38 (1.23-1.57) g/L, p = 0.57]. C3a predicted the 5-year mortality of the patients [C3a > 165 ng/mL hazard ratio = 4.21 (1.65-10.72), p = 0.003] independent of the NT-proBNP and other factors. After reclassification, we observed a significant net reclassification improvement [NRI = 0.71 (0.43-0.98), p < 0.0001] and integrated discrimination improvement [IDI = 0.08 (0.03-0.12), p = 0.0002]. Conclusions: In patients with CRT, elevated C3a levels increase the risk of mortality independent of the NT-proBNP levels or other factors. CRT exerts anti-inflammatory effect by reducing the complement activation. [ABSTRACT FROM AUTHOR]

Mast cell degranulation triggers hypersensitivity reactions at the body-environment interface. Adenosine modulates degranulation, but enhancement and inhibition have both been reported. Which of four adenosine receptors (ARs) mediate modulation, and how, remains uncertain. Also uncertain is whether adenosine reaches mast cell ARs by autocrine ATP release and ecto-enzymatic conversion. Uncertainties partly reflect species and cell heterogeneity, circumvented here by focusing on homogeneous human LAD2 cells. Quantitative PCR detected expression of A, A, and A, but not A, ARs. Nonselective activation of ARs with increasing NECA monotonically enhanced immunologically or C3a-stimulated degranulation. NECA alone stimulated degranulation slightly. Selective AR antagonists did not affect C3a-stimulated degranulation. NECA's enhancement of C3a-triggered degranulation was partially inhibited by separate application of each selective antagonist, and abolished by simultaneous addition of antagonists to the three ARs. Only the A antagonist separately inhibited NECA's enhancement of immunologically stimulated degranulation, which was abolished by simultaneous addition of the three selective antagonists. Immunological or C3a activation did not stimulate ATP release. NECA also enhanced immunologically triggered degranulation of mouse bone marrow derived mast cells (BMMCs), which was partially reduced only by simultaneous addition of the three antagonists or by the nonselective antagonist CGS15943. BMMCs also expressed A, A, and A ARs. but not AAR detectably. We conclude that (a) AAR is unnecessary for LAD2 degranulation or AR enhancement; (b) A, A, and A ARs all contribute to pharmacologic AR enhancement of LAD2 and BMMC degranulation; and (c) LAD2 cells depend on microenvironmental adenosine to trigger AR modulation. [ABSTRACT FROM AUTHOR]

Background: IgA nephropathy (IgAN) is the most common primary kidney disease, often leading to chronic renal failure. Complement activation products C3a and C5a have broad pro-inflammatory potential through their receptors, C3aR and C5aR, and contribute to the pathogenesis of several inflammatory and autoimmune diseases, but their roles in IgAN are poorly defined. Purpose: This study aimed to establish correlations between renal C3a, C5a, C3aR, C5aR, or serum/urinary C3a, C5a with clinical features and renal histopathology in patients with IgAN. Methods: Eighty-three patients with renal biopsy proven IgAN were investigated. Thirty patients fulfilled Haas's II, 30 fulfilled Haas's III and 23 fulfilled Haas's IV criteria. Deposition of C3a and C5a was assessed by immunohistochemistry. C3aR and C5aR mRNAs and proteins in kidney tissue were examined by real-time quantitative PCR (RT-qPCR) and immunohistochemical staining, respectively. C3a and C5a levels were quantified by ELISA in serum and urine samples of 30 IgAN patients, 10 control subjects and 10 septic patients. Results: Renal C3a and C5a deposition and C3aR and C5aR expression increased with increasing grades of renal pathology in IgAN patients. They positively correlated with proteinuria and serum creatinine (SCr), but not serum C-reactive protein (CRP) or complement 3 (C3). Serum C3a and C5a increased to levels comparable to septic patients but did not differ among IgAN sub-groups. In contrast, urinary C3a and C5a increased significantly and correlated positively with renal pathological grades. Conclusions: In patients with IgAN, urinary and renal C3a and C5a and renal expression of C3aR and C5aR are significantly correlated with the activity and severity of renal injury. This observation warrants further study into the roles of C3a, C5a and their receptors in the pathogenesis of IgAN and as potential therapeutic targets. [ABSTRACT FROM AUTHOR]

Activation of the complement system plays a crucial role in the pathogenesis of infection and inflammation. Especially the complement activation products C3a and C5a, known as the anaphylatoxins, are potent proinflammatory mediators. In addition to their evident role in innate immunity, it is clear that the anaphylatoxins also play a role in regulation of adaptive immune responses. The anaphylatoxins play a role in a variety of infectious and inflammatory diseases like sepsis, ischemia-reperfusion injury, immune complex diseases, and hypersensitivity diseases like asthma. In this review we discuss the role of anaphylatoxins in infection and inflammation. Furthermore, we focus on bacterial complement evasion strategies that can provide tools for further research on pathogenesis of infectious diseases and a better understanding of the role of complement and anaphylatoxins in infection and inflammation. [ABSTRACT FROM AUTHOR]

Mice deficient in complement C3 (C3-/-) are hematologically normal under steady-state conditions, and yet displayed a significant delay in hematopoietic recovery from either irradiation or transplantation of wild-type (WT) hematopoietic stem/progenitor cells (HSPC). Transplantation of histocompatible WT Sca-1+ cells into C3-/- mice resulted in a (i) decrease in day 12 CFU-S, (ii) 5-7-day delay in platelet and leukocyte recovery, and (iii) reduced number of BM CFU-GM progenitors at day 16 after transplantation. Nevertheless, HSPC from C3-/- mice engrafted normally into irradiated WT mice, suggesting that there was a defect in the hematopoietic environment of C3-/- mice. Since C3-/- mice cannot activate/cleave C3, the C3 fragments C3a, C3ades-Arg, and iC3b were examined for a role in HSPC engraftment. Liquid-phase C3a and C3ades-Arg increased CXCR4 incorporation into membrane lipid rafts (thus potentiating HSPC responses to SDF-1 gradients), whereas iC3b was deposited onto irradiated BM cells and functioned to tether CR3(CD11b/CD18)+HSPC to damaged stroma. The activity of C3ades-Arg suggested that C3aR+HSPC also expressed the C5L2 (receptor for C3a and C3ades-Arg) and this was confirmed. In conclusion, a novel mechanism for HSC engraftment was identified, which involves complement activation and specific C3 fragments that promote conditioning for transplantation and enhance HSPC engraftment.Leukemia (2004) 18, 1482-1490. doi:10.1038/sj.leu.2403446 Published online 29 July 2004 [ABSTRACT FROM AUTHOR]

Inflammatory mediators involved in the pathogenesis of the adult respiratory distress syndrome (ARDS) are products of the humeral cascade systems like the complement cascade and substances released from neutrophil granulocytes and macrophages like proteases, O-radicals and arachidonate products. Phospholipase A (PLA) was shown by Vadas et al. to be correlated with circulatory shock in the sepsis syndrome, the probably most important underlying disease of ARDS. In a clinical study in 48 patients at risk for ARDS after trauma and sepsis we found plasma PLA elevated (52±5 U/l) in sepsis, with a positive correlation to the complement split product C3a ( r=0,42, p<0,01) and neopterin ( r=0,49, p<0,05), which serves as a marker of macrophage stimulation. Elastase-α1PI and C3a showed higher plasma levels in patients with ARDS compared with non-ARDS patients, whereas the neopterin and PLA concentrations were not different with regard to ARDS. The relation between PLA and neopterin shown in the study is consistent with the possibility of macrophages being a source of the plasma PLA, as reported in experimental studies. [ABSTRACT FROM AUTHOR]

Complement conversions and a pulmonary leukocyte sequestration were observed during cardiopulmonary bypass (CPB) in all of twenty patients who received open heart surgery. A systemic neutropenia was initially observed in the early phase of CPB, and it subsequently turned into a systemic neutrocytosis during the late phase of it. A significant leukocyte sequestration was found in the pulmonary circulation during CPB coincidently with the systemic neutropenia. The contribution of the transpulmonary sequestration to the leukopenia was major, being as high as 80 per cent. Plasma C3, C4, and CH50 levels rapidly decreased following the commencement of CPB. Alterations of the C3 molecule in the patients' plasma were demonstrated using the immunoblotting method. The appearances of C3a and C3b with the apparent molecular weights of 10,000 and 170,000 respectively, might be evidence of the complement activation during CPB. Another type of alteration in the C3 molecule was observed in the generation of a new fragment with the apparent molecular weight of 14,000. The appearance of this fragment, which did not share common epitopes with C3a, might suggest the consumption of complement components during CPB, unrelated to the activation of the complement systems. [ABSTRACT FROM AUTHOR]

The hydration of C3A with and without CaCO3 was studied. The techniques used were X-ray diffraction, thermogravimetry, differential thermogravimetry and calorimetry. In the presence of CaCO3, the hydration of C3A is accelerated. The hexagonal hydrates are formed first. They react with CaCO3 to form calcium carboaluminate hydrate. This reaction blocks formation of the cubic hydrate. The latter appears when CaCO3 is completely consumed. [ABSTRACT FROM AUTHOR]

Normal complement components and activation products were determined in the peripheral blood of 35 patients with atopic dermatitis (AD) and 24 patients with psoriasis at a mild to intermediate stage. None of the patients had received systemic or local steroid therapy 6 weeks prior to blood collection. Levels of C3, C4 and C1 inactivator (C1 INA) were determined in serum by radial immunodiffusion, whereas C3a and C5a levels were measured by radioimmunoassay. In comparison to healthy non-atopic controls, the levels of C3, C4 and C1 INA were found to be significantly increased in both diseases. No substantial differences were detected between patients with psoriasis vulgaris and psoriasis guttata, which suggests that the dissimilarities found were not due to preceding or concomitant infections. In AD, there was a tendency towards increased C3a levels, whereas in psoriasis, C3a levels were significantly increased. In both diseases, no measurable amounts of C5a could be detected. The results indicate that, in both AD and psoriasis, the complement participates in the inflammatory process. Elevated levels of C3a suggest that there is a continuous activation of the complement system leading to the generation of inflammatory mediators. [ABSTRACT FROM AUTHOR]